DoJo

Hey there,

What would cause fuse 11 (run/start ignition) to blow?
What circuts should I be checking.

All help would be greatly appreciated....

DOJO

CCKen

Fuse F11 (20 Amp) in the Junction Block?

It feeds the:

Power Train Control Module (connector C1, pin A2)

Automatic Shut Down Relay

Fuel Pump Relay

You can pull each of the relays, in turn, and put the key to RUN/engine off, and see if the fuse blows. If neither relay blows the fuse, the wire to the PCM may be shorted to ground. In this case you would wiggle the wire harnesses in the engine bay and see what happens.

Fuse F11 (30 Amp) in the Power Distribution Center feeds the Rear Window Defogger Relay in the Junction Block. If this is the fuse you're talking about, pull this relay, like the other relays mentioned above, and see if the fuse blows.

freegdr

in cab or pbc under hood?

cdhebert

Crawl under your Jeep and look at your rear O2 sensor. I bet you a dollar that the wire is hanging down and rubbing the driveshaft. The heater circuit for the O2 runs through the PCM. If you ground that wire, it blows your PCM fuse. Fix that wire and attach it up out of harms way.

freegdr

Yep was getting to this .

DoJo

Hey Guy's thanks for the reply...

There's more to add to this now

Checked everything mentioned above and checked out OK - but what I noticed is that fuse 11 (located in the passenger foot well) blows when I put it into reverse and give it the gas.
I then threw a crankshaft position code.
Replaced it with a Jeep OEM part.
Started it up put it into reverse it hesitated a little and threw the code again.
I'm ready to throw in the towel - does anyone know of a good jeep mechanic in the Hartford, ct area??

Thanks again for everyone's help..

DoJo

klump

my immediate thought is that your reverse lights might be shorted to ground somewhere, but the crankshaft code and the fact that you have to give it gas to blow throw me off.

CCKen

Are you sure it's not fuse F10 (15 Amp) just above F11? F10 feeds the transmission range sensor (NSS), which may account for the problem when you select reverse.

DoJo

I'm sure - it's the 4th spot from the bottom - looked in the owners manual and it's cavity 11.
I wish it was F10, I checked it and it's fine...

cdhebert

I thought you meant the distribution block under the hood. My bad.
On mine ('98), fuse 11 in the interior fuse panel is for Run/Start/Ignition and DRL.
I'd start chasing the wiring to/from both the starter and the alternator. Something is grounding out. The only way fuses blow is an overload or short. If you haven't added any heavy drain items to your electrical system, it would most likely be a wire shorting out somewhere.
Don't rule out the NSS either.
Just for fun, you could pull the power connector off the alternator and check continuity between the alternator output wire, and the body of the alternator (ground). There should be none. If there is, you have a bad alternator. It is rare for them to fail like that, though. You can also do the same thing with the starter itself, only check it across the ignition post and the ground.
I wish I had a more pinpoint answer for you.

cdhebert

That was supposed to say 98. I don't know where that stupid smiley face came from.

CCKen

Just found a more current wiring diagram that shows F11 feeding the TCM, pin 26.

From F11 the wire goes through two splices before it gets to the TCM that I would have to look up, but in the mean time, you may want to detach the connector from the TCM and see what happens.

Can't figure out why you would get a crank sensor code along with the F11 problem.

What is the code number?

CCKen

99 XJ F11 TCM/TCA diagram:

DoJo

Not to sound to stupid where is the tcm located?
Also the code number is 1391...

I appreciate all the info you are giving...

DoJo

CCKen

The TCM is located under the dash by the steering column.



P1391 is:

CMP=Camshaft Position Sensor, CKP=Crankshaft Position Sensor

P1391-INTERMITTENT LOSS OF CMP OR CKP

Possible Causes

CMP SENSOR OUT OF SYNC
DAMAGED TONE WHEEL/FLEX PLATE (CRANKSHAFT)
DAMAGED TONE WHEEL/PULSE RING (CAMSHAFT)
INTERMITTENT CKP SIGNAL LOSS WHEN WIRING IS WIGGLED
WIRING HARNESS INTERMITTENT
SENSOR CONNECTOR/WIRING
SENSOR CONNECTOR/WIRING
CAMSHAFT POSITION SENSOR
CKP SENSOR CONNECTOR/WIRING
CRANKSHAFT POSITION SENSOR

Note the intermittant wiring harness and the signal loss when the wiring is wiggled. The XJ wiring is subject to chaffing, especially in the engine bay. Wiggling wiring harnesses and visual inspection of wiring and connectors are routine diagnostics for XJ's. You may want to give this a try.
TEST